STATE OF THE ART
The invention relates to a clip for holding and/or keeping together sheets of paper or other materials, or for placing on/against other objects of different types, comprising two holding legs of sheet-type material lying essentially in parallel planes and springing relative to each other, and of which the two end edges cross at an angle relative and form, when in use, with at least part of their lengths, push-on edges, defining a reverse V-shaped push-on space, at least one of said holding legs being bent in such a way that a part adjacent to the connecting line with the other leg lies at a distance from said other leg, and a second part, essentially ending at the push-on edge, lies with at least a part of its inside essentially flat against the inside of a part of the other holding leg.
A clamp of this type is disclosed in U.S. Pat. No. 1,637,564. It has the advantage in being fit for providing information on parts of the plate material, and is also fit to hide for example staples. However, the substantially V-shaped push-on space is formed for the greater part by two points in which the foremost holding leg ends. The rear holding leg is shorter and ends in a single point in the middle of the width. In order to create a push-on facility all these points are curved rearwardly. By this, they are inclined to introduce damages, by scratches or folds, onto the paper or the other material which they hold together, or on which they have been placed, both when placing them and with removing them. Furthermore the parts of the front and rear holding legs, initially lying one against the other, will not remain flat against each other when one or several sheets of paper are inbetween them; the contact is limited to a line contact. As a result the capacity is very much limited and also the risk increases that the rear holding leg is being gripped and thereby pulled off the pile of sheets.
Also a clip for paper is known which comprises two holding elements lying essentially in parallel planes and springing relative to each other, and of which the two end edges run at an angle relative to each other, and form push-on edges when in use, which edges define a V-shaped push-on space. This is a paper clip of spring steel wire (as a variation of the most common type of paper clip with two semi-circular push-on ends lying some distance apart).
A major disadvantage lies in the thickness arising from the diameter of the steel wire from which they are made, and from the fact that the paper will bend through the gripping action. Also the deformation when pushing on is concentrated as torsion of the part of the wire which constitutes the connection between the two holding members; thereby these holding members will not lie anymore parallel to each other and flatly against the paper which is being clamped, but they will stand outwards, so that there will be no flat clamping effect. When a number of piles all containing such paper clips on the same corner, are stacked up, a thickening which is a multiple of the thickness of the whole pile of paper is very soon produced at the corner.
Ordinary and special paper clips are known (WO 81/01535) which can be provided with client-specific identification; they are expensive, however. Besides, they cannot be used together with permanent holders (e.g. staples), or at least they provide no possibilities for masking the common staple.